the back and top are in place,with a border of rosewood around them.
the strings will be held in place with a tail piece like a mandolin or a banjo has. make the bridge out of solid hardwood. make it thin,and tall enough to keep the strings off the frets.
the soundboard will sink in some so don't get too close to the frets till it's been strung for a few days. then you can trim the bridge if you like.